Automatic storage and retrieval systems are used in warehouses or other facilities in which objects are to be temporarily stored. A known storage and retrieval system includes a storage rack defining storage compartments or locations, and a storage and retrieval machine (SRM) operable to deposit objects in designated storage locations on the storage rack and to retrieve those objects when desired. The storage and retrieval machine is supported for horizontal movement along a track, and the machine includes a vertically extending mast that supports a carriage for vertical movement. The carriage supports an extractor or shuttle mechanism that is horizontally extendable beneath an object and retractable from beneath the object so that the object can be lifted from or lowered onto the storage rack.